#!/usr/bin/env python
# -*- coding:utf-8 -*-
# Author: G171117 JieJiSS

print("90÷41×38+490÷50=", 90 / 41 * 38 + 490 / 50, sep='')
print("(27-18)×27=", (27 - 18) * 27, sep='')

print("(6968-864)/56=", (6968 - 864) / 56, sep='')
print("200*3/5-80=", 200 * 3 / 5 - 80, sep='')
print("600*(1/4+2/5)=", 600 * (1 / 4 + 2 / 5), sep='')

def trapezoid_area(upper_width, lower_width, height):
    r"""
    计算梯形面积
    """
    return (upper_width + lower_width) * height / 2

PI = 3.1416
S1 = trapezoid_area(8 + 3, 16, 8)
S2 = 1 / 4 * PI * 8 ** 2
print("阴影部分面积为", S1 - S2, sep='')
